Laminated glass with functional ultra-fine particles and method of producing same

ABSTRACT

The invention provides a laminated glass and a method of producing the same. This laminated glass includes first and second transparent glass plates and an interlayer film interposed therebetween. This interlayer film has functional ultra-fine particles which have a particle diameter of up to 0.2 μm and are dispersed therein. Due to the incorporation of the ultra-fine particles thereinto, the interlayer film is provided with various additional functions such as heat insulation, ultraviolet ray absorption and the maintenance of a sufficient radio transmittance. Therefore, the laminated glass becomes suitable as an architectural or automotive laminated glass.

This application is a division of application Ser. No. 08/588,963, filedJan. 19, 1996 now U.S. Pat. No. 5,830,568.

BACKGROUND OF THE INVENTION

The present invention relates to a laminated glass with an interlayerresinoid film containing functional ultra-fine particles dispersedtherein and a method of producing this laminated glass.

There have been proposed colorless or colored architectural glasseshaving functions of heat insulation, ultraviolet ray insulation andimproved radio wave transmission. Furthermore, there have been proposedautomotive glasses having a function of heat insulation for insulatingsolar radiation energy incident on car interior and thus for loweringthe air conditioning load, and a function of ultraviolet ray insulation.Recently, there has been an increasing demand for an architectural orautomotive laminated glass having functions of heat insulation,ultraviolet ray insulation, and improved radio wave transmission, whilethis glass has a sufficient visible light transmittance.

There are several proposals that fine particles are contained in theinterlayer film of laminated glass, for providing the laminated glasswith a certain function(s). For example, Japanese Patent UnexaminedPublication JP-A-2-22152 discloses an interlayer film of laminatedglass, for insulating short wavelength light rays. This interlayer filmis made of a plasticized polyvinyl butyral containing at least one lightabsorbing agent selected from special benzotriazole derivatives and aninorganic matter in the form of fine powder. 90% by weight of thisinorganic matter has a particle diameter within a range from 250 to 400nm. This interlayer film is characterized in that light rays of up to400 nm wavelength is substantially insulated and that light rays of atleast 450 nm wavelength is substantially transmitted therethrough. Thelight absorbing agent's content is from 0.4 to 6 wt %, and the inorganicmatter's content is from 2 to 17 wt %.

As another example, Japanese Patent Unexamined Publication JP-A-4-160041discloses an automotive window glass having a layer interposed betweentransparent platelike members. This layer is made of a mixture of aglass component and ultra-fine particles having an average diameter ofup to 0.1 μm. The glass component is an organic silicon or an organicsilicon compound and serves to bond together at a relatively lowtemperature two glass plates of a laminated glass or an inter resinoidfilm and a glass plate. The ultra-fine particles has a function oftransparent electric conductiveness, infrared reflection function,electromagnetic insulation function.

Japanese Patent Unexamined Publication JP-A-4-261842 discloses alaminated glass comprising an organic glass member, a transparentmember, and an interlayer film interposed therebetween. This interlayerfilm contains 100 parts by weight of an ethylene-ethylacrylatecopolymerized resin prepared by graft modification of a vinylsilane and3-30 parts by weight of optional silicon dioxide fine particles. Whenthe particle diameter of the fine particles is from 0.1 to 400 nm,scatter of light rays which are transmitted through the interlayer filmcan be prevented.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a laminated glasswhich has a good quality requisite for an architectural or automotivelaminated glass itself and of which interlayer film has variousadditional functions such as heat insulation, ultraviolet ray absorptionand the maintenance of a sufficient radio transmittance.

According to a first aspect of the present invention, there is provideda laminated glass comprising:

first and second transparent glass plates;

an interlayer film interposed between said first and second glassplates; and

functional ultra-fine particles which have a particle diameter of up to0.2 μm and are dispersed in said interlayer film.

According to a second aspect of the present invention, there is provideda method of producing a laminated glass, comprising the steps of:

(a) interposing an interlayer film between first and second glassplates, said interlayer film having functional ultra-fine particleswhich are dispersed therein and have a particle diameter of up to 0.2μm; and

(b) bonding together said first and second glass plates and saidinterlayer film.

As is mentioned above, a laminated glass according to the presentinvention has an interlayer film containing ultra-fine particles whichhave a particle diameter of up to 0.2 μm and are dispersed in theinterlayer film. With this, the laminated glass has various additionalfunctions such as the provision of colorlessness or a certain desiredcolor tone, heat insulation, ultraviolet ray insulation, the maintenanceof a sufficient radio transmittance, and the like, without adding anadverse effect on the interlayer film's basic characteristics requisitefor an architectural or automotive laminated glass. Therefore, thelaminated glass is capable of improving the air conditioning effect andinhabitability of automobile, building and the like, of reducing anadverse effect of ultraviolet rays on the interior of automobile,building or the like, and of maintaining a sufficient radiotransmittance equivalent to that of a conventional float glass, forreceiving and transmitting radio waves.

A laminated glass according to the present invention is well controlledin color tone, extremely low in haze value, and superior in transparencyand in reduction of reflection and glare. For example, the laminatedglass has requisite basic characteristics for an automotive safetyglass. These basic characteristics are substantially equivalent to thoseof conventional automotive laminated glass and provide satisfactoryresults in various tests of Japanese Industrial Standard (JIS) R 3212and the like.

In a method of producing a laminated glass according to the presentinvention, it is not necessary to use a glass plate having a specialcomposition nor a glass plate having a special surface finish. Aconventional production line for producing conventional laminatedglasses can be used for producing a laminated glass of the presentinvention. Therefore, the laminated glass can be easily and economicallyproduced. Furthermore, it can be flexibly produced according to the sizeand shape of the laminated glass.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, a laminated glass according to the present inventionwill be described in detail. This laminated glass comprises first andsecond transparent glass plates and an interlayer film interposedtherebetween. The interlayer film has functional ultra-fine particleswhich have a particle diameter of up to 0.2 μm and are dispersedtherein. These particles are used to provide various functions such asheat insulation, thereby maintaining the solar radiation transmittancewithin a range of up to 65%, while the scattering and reflection of thevisible light rays is suppressed. In spite of the fact that theinterlayer film contains the functional ultra-fine particles, it hasbeen unexpectedly found that the laminated glass has an extremely lowhaze value, a good radio transmittance and a sufficient transparency andthat the interlayer film is sufficient in bond strength against thefirst and second glass plates, in transparency, durability and the like.Even though the interlayer film contains the functional ultra-fineparticles, the laminated glass can be produced in a production line forconventional laminated glasses. The functional ultra-fine particles havea particle diameter preferably up to 0.15 μm or from 0.001 to 0.2 μm,more preferably from 0.001 to 0.15 μm or from 0.002 to 0.15 μm, andstill more preferably from about 0.001 to about 0.10 μm or from about0.002 to about 0.10 μm. It is preferable that these particles have anarrow particle diameter distribution, for example, within a range about0.01 to about 0.03 μm.

In the invention, it is preferable that the functional ultrafineparticles amount to up to 10.0 wt % based on the total weight of theinterlayer film. With this, these particles have various functions suchas heat insulation, for example, to maintain the solar radiationtransmittance within a range of up to 65%, while a first condition thatthe laminated glass has an extremely low haze value, a sufficient radiotransmittance and a sufficient transparency is satisfied, while a secondcondition that the interlayer film is sufficient in bond strengthagainst the first and second glass plates, in transparency, durabilityand the like is satisfied, and while a third condition that thelaminated glass can be produced by a production line for conventionallaminated glasses is satisfied. If the amount of the functionalultra-fine particles exceeds 10.0 wt %, it becomes difficult to satisfythe above-mentioned first, second and third conditions. When thelaminated glass is used as an architectural glass having a visible lighttransmittance (Tv) of at least 35%, it is necessary to add theultra-fine particles made of inorganic pigment(s) in an amount within arange from about 0.1 to about 10 wt %. In general, in the production ofthe laminated glass as an architectural glass, the amount of theultra-fine particles is preferably from about 0.01 to about 9 wt % andmore preferably from about 0.05 to about 8 wt %. In general, in theproduction of the laminated glass as an automotive glass, the amount ofthese particles is preferably from about 0.01 to about 2.0 wt % and morepreferably from about 0.1 to about 1.0 wt %. In conclusion, the amountof these particles is decided according to the balance between theabove-mentioned additional functions of these particles and the basiccharacteristics of the laminated glass. That is, if the amount of theseparticles is too much, the additional functions of these particlesbecome sufficient, but the basic characteristics of the laminated glassmay be impaired. On the contrary, if the amount of these particles istoo little, the basic characteristics of the laminated glass aremaintained, but the additional functions of these particles becomeinsufficient.

In the invention, the interlayer film is not limited to a particularmaterial, but preferably made of a polyvinyl butyral (PVB) or anethylene-vinylacetate copolymer (EVA), which is generally used as amaterial for the interlayer film. Examples of the material of theinterlayer film are a plasticized PVB made by Sekisui ChemicalIndustries, Ltd., Monsant Japan, Ltd. or the like, an EVA made by Dupont Co. or Takeda Chemical Industries, Ltd. (DUMILAN (trade name)), anda modified EVA (e.g., MERUCENE G (trade name) made by Toso Co.). It isoptional to add an additive(s) to the interlayer film, such asultraviolet absorbing agent, antioxidant, antistatic agent, heatstabilization agent, lubricant, filler, coloring agent, and bondadjusting agent.

It is optional that the interlayer film according to the presentinvention is placed on a conventional interlayer film to prepare alaminate, and then this laminate is interposed between the first andsecond glass plates to prepare the laminated glass. Furthermore, it isoptional that the interlayer film according to the present invention isinterposed between first and second conventional interlayer films toprepare a laminate to be interposed between the first and second glassplates.

In the invention, it is preferable that the functional ultra-fineparticles comprise at least one member selected from the groupconsisting of metals, compounds containing the metals, and compositescontaining the metals. These metals consist of Sn, Ti, Si, Zn, Zr, Fe,Al, Cr, Co, Ce, In, Ni, Ag, Cu, Pt, Mn, Ta, W, V and Mo. The compoundscontaining the metals consist of oxides of the metals, nitrides of themetals, oxynitrides of the metals, and sulfides of the metals. Thecomposites containing the metals consist of the metals doped with atleast one substance, and the compounds doped with the at least onesubstance. The at least one substance is selected from the groupconsisting of antimony, antimony compounds, fluorine, fluorinecompounds, stannous compounds, and aluminum compounds. The functionalultra-fine particles may comprise a mixture of the above-mentioned atleast one member and an organic resin. This mixture may be the at leastone member coated with this organic resin.

Examples of the above-mentioned oxides of the metals for the functionalultra-fine particles are SnO₂, TiO₂, SiO₂, ZrO₂, ZnO, Fe₂O₃, Al₂O₃, FeO,Cr₂O₃, Co₂O₃, CeO₂, In₂O₃, NiO, MnO and CuO. Exemplary commercialproducts of the functional ultra-fine particles made of TiO₂ are IT-S-UD(trade name) which is made by Idemitsu Petrochemical Co., Ltd. and has aparticle diameter of 0.02 μm, and UFO1 (trade name) which is made by TaiOxide Chemicals Co. and has a particle diameter of 0.018 μm. Anexemplary commercial product of the functional ultra-fine particles madeof Fe₂O₃ is NANOTITE (trade name) which is in the form of sphericalultra-fine hematite particles, has a particle diameter of 0.06 μm and ismade by Showa Denko K.K. Examples of the above-mentioned nitrides of themetals are TiN and AlN. An example of the above-mentioned sulfides ofthe metals is ZnS. Examples of the metals with doped with the at leastone substance are SnO₂ doped with 9 wt % Sb₂O₃ (ATO) made by SumitomoOsaka Cement Co., SnO₂ doped with fluorine, and SnO₂ doped with 10 wt %Sb₂O₃. Examples of mixtures (composites) each containing at least two ofthe above-mentioned metals are In₂O₃-5 wt % SnO₂ (ITO) made byMitsubishi Material Co., and inorganic pigment ultra-fine particles suchas Co₂O₃—Al₂O₃ (e.g., TM3410 (trade name) having a particle diameterfrom 0.01 to 0.02 μm), TiO₂—NiO—Co₂O₃—ZnO (e.g., TM3320 (trade name)having a particle diameter from 0.01 to 0.02 μm) and Fe₂O₃—ZnO—Cr₂O₃(e.g., TM3210 (trade name) having a particle diameter from 0.01 to 0.02μm). TM3410, TM3320 and TM3210 are made by Dai Nichi Seika Kogyo Co.Examples of the above-mentioned organic resin to be used together withthe above-mentioned at least one member are fluorine compounds such asfluororesins, polytetrafluoroethylene (PTFE), LUBURON (trade name) madeby Daikin Industries, Ltd., CEFRAL LUBE (trade name) of Central GlassCo., Ltd., and low molecular weight trifluoroethylene (TFE), siliconeresins, silicone rubbers. Of the above examples, ATO and ITO areparticularly preferable examples as the functional ultra-fine particlesfor an automotive laminated glass.

The above-mentioned organic resin is used to reduce bond strengthbetween the PVB film and the first and second glass plates. In otherwords, in case that, for example, ATO or ITO is used as the functionalultra-fine particles, the bond strength may become too much. In thiscase, the organic resin is used to lower the pummel value and thus toreduce the bond strength to a permissible standard range. Thus, thepurpose of the addition of the organic resin is similar to that of theprimer coating on the glass plate surface or to that of the coating ofthe organic resin film made of fluororesin, silicone resin, siliconerubber or the like.

By the incorporation of the functional ultra-fine particles into theinterlayer film, the laminated glass is provided with various functionssuch as heat insulation, ultraviolet ray insulation, the provision ofcolorlessness or a certain desired color tone, light insulation and thelike.

In the invention, the interlayer may contain an organicultraviolet-ray-absorbing agent. Examples of this agent arebenzotriazole derivatives such as 2-(2′-hydroxy-5′-methylphenyl)benzotriazole, 2-(2′-hydroxy-3′,5′-ditert-butylphenyl) benzotriazole,2-(2′-hydroxy-3′-tert-butyl-5′-methylphenyl)-5-chlorobenzotriazole2-(2′-hydroxy-3′,5′-ditert-butylphenyl)-5-chlorobenzotriazole and2-(2′-hydroxy-3′,5′ditert-amylphenyl) benzotriazole, benzophenonederivatives such as 2,4-dihydroxybenzophenone,2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-octoxybenzophenone,2-hydroxy-4-dodecyloxybenzophenone,2,2′-dihydroxy-4-methoxy-benzophenone,2,2′-dihydroxy-4,4′-dimethoxybenzophenone and2-hydroxy-4-methoxy-5-sulfobenzophenone, and cyanoacrylate derivativessuch as 2-ethylhexyl-2-cyano-3,3′-diphenylacrylate andethyl-2-cyano-3,3′-diphenylacrylate. An example of commercial productsof the organic ultraviolet-ray-absorbing agent is TINUVIN327 (tradename) made by Ciba-Geigy Co.

In the invention, the interlayer film may contain an organicheat-absorbing agent(s). Examples of this agent are NIR-AM 1 made byTeikoku Chemical Industries, Ltd., and as near infrared rays absorbingagents SIR-114, SIR-128, SIR-130, SIR-132, SIR-169, SIR-103, PA-1001 andPA-1005 which are made by Mitsui Toatsu Chemicals, Inc. The interlayerfilm may further contain a pigment(s).

A laminated glass according to the present invention can be used as anarchitectural window glass or an automotive window glass such as a frontwindshield, a rear windshield with or without a shade band, a sidewindshield, or a sunroof.

In general, the sheet (surface) resistivity of a glass plate with glassantenna is preferably at least 20 MΩ/□. In particular, when the glassplate is in contact with the antenna, the sheet resistivity ispreferably at least 10 MΩ/□. If it is less than 10 MΩ/□, the differencebetween the sheet resistivity of a laminated glass and that of a glassplate itself may be at least 1 dB as an absolute value. The sheetresistivity of the laminated glass is preferably at least 15 MΩ/□ formaintaining this difference within 0.8 dB (absolute value). The sheetresistivity of the laminated glass is preferably within a range fromabout 20 MΩ/□ to about 10 GΩ/□ and more preferably within a range fromabout 22 MΩ/□ to about 10 GΩ/□ for obtaining a satisfactory radio wavetransmittance, satisfactory optical characteristics and satisfactoryphysical and chemical characteristics.

In the invention, it is possible to obtain a laminated glass which issuperior in radio wave transmittance, heat insulation, ultraviolet raysinsulation and optical characteristics. This laminated glass isparticularly suitable as an automotive windshield. In more detail, thislaminated glass as an automotive windshield has a radio transmittancewhich is equivalent to that of a glass plate itself, a solar radiationtransmittance of up to 65% thereby improving a so-called automotiveinhabitability, a visible light transmittance of at least 65% or atleast 70% thereby allowing the driver and a passenger(s) to have a goodview, and a very low visible light reflectance thereby allowing thedriver and a passenger(s) to have a good view, avoid misreading oftraffic control signal and the like, and minimize the eye fatigue. As anautomotive glass plate, it is preferable that the laminated glass has avisible light transmittance of at least 68 or 70%, a visible lightreflectance of up to 14%, a solar radiation transmittance of up to 60%,and an excitation purity of up to 15 or 10%. As an architectural glassplate, it is preferable that the laminated glass has a visible lighttransmittance of at least 30%, a visible light reflectance of up to 20%,a solar radiation transmittance of up to 65%, and an excitation purityof up to 20%.

The arrangement of the interlayer film is flexible according to need. Inother words, for example, the interlayer film may be sized and arrangedsuch that the interlayer film is not formed on a position correspondingto the peripheral portion of the laminated glass, nor on a positioncorresponding to the feeding point(s), nor on a position correspondingto a portion on which a molding is formed, nor on a positioncorresponding to the whole or a part of the electric conductor portionof an antenna.

According to the invention, the interlayer film has a heat insulationcharacteristic and a high sheet-resistivity equivalent to that of asemiconductor film or of an insulating film. Therefore, a the laminatedglass of the invention does not cause radio disturbance in receiving AMradio waves, FM radio waves and the like, nor radio interference such asghost image of the TV picture. Even in case that a film which has a highresistivity and a heat insulation characteristic is formed on a glassantenna device, the radio receiving capacity of the laminated glass isnot be lowered.

The first and second glass plates of the laminated glass may be made ofan organic glass or a composite glass of inorganic and organic materialsand may be colorless or colored float glass plates. This colored floatglass plates may have a color of green, bronze, gray or blue. The firstand second glass plates may be flat or curved and used for a multipleglass, a by-layer glass, or the like. In general, it is preferable thatthe first and second glass plates have a thickness, for example, fromabout 1.0 mm to about 12 mm. For architectural use, these plates have athickness preferably from about 2.0 mm to about 10 mm. For automotiveuse, these plates have a thickness preferably from about 1.5 mm to about3.0 mm and more preferably from about 2.0 mm to about 2.5 mm.

In the following, a method of producing a laminated glass will bedescribed in detail in accordance with the present invention. Thismethod comprises the steps of:

(a) interposing an interlayer film between first and second glassplates, the interlayer film having functional ultra-fine particles whichare dispersed therein and have a particle diameter of up to 0.2 μm; and

(b) bonding together the first and second glass plates and theinterlayer film.

It is preferable that the step (b) is conducted in an autoclave by acommon autoclave method, or under reduced pressure for a period of timefrom 20 to 30 minutes, while an ambient temperature was raised from 80to 120° C. With this, the interlayer film will have uniformly unevenembossing thereon. However, in some cases, the step (b) may be conductedby one of various simpler methods.

In the following, a method of preparing the interlayer film will bedescribed in detail in accordance with the present invention. Thismethod comprises the steps of:

(c) dispersing up to 80.0 wt % of the functional ultra-fine particles ina plasticizer solution, based on the total weight of the plasticizersolution and the ultra-fine particles, so as to prepare a first mixture;

(d) adding up to 50 wt % of the first mixture to a PVB or to an EVA,based on the total weight of the PVB or EVA, so as to prepare a secondmixture;

(e) optionally adding at least one additive to the second mixture so asto prepare a third mixture; and

(f) kneading the third mixture to uniformly disperse therein thefunctional ultra-fine particles, thereby to prepare a raw material ofthe interlayer film.

During the step (c), the functional ultra-fine particles can be welluniformly dispersed in the plasticizer solution. Therefore, the firstmixture becomes superior in transparency. During the step (c), if theamount of the functional ultra-fine particles exceeds 80.0 wt %, itbecomes difficult to get uniformly dispersed ultra-fine particles. Theamount of the ultra-fine particles is preferably up to about 20.0 wt %,more preferably up to about 10.0 wt %, and still more preferably withina range from 0.5 to 5.0 wt %. If the amount of the ultra-fine particlesis too small, the advantageous effect of the addition may becomeinsufficient.

During the step (d), if the amount of the first mixture exceeds 50 wt %,the ultra-fine particles may not be uniformly dispersed in the PVB orthe EVA, and the interlayer film's basic characteristics may becomeunsatisfactory. During the step (d), the amount of the first mixture ispreferably up to about 45 wt % and more preferably within a range fromabout 10 wt % to about 40 wt %. During the step (f), the third mixtureis kneaded by a common mixer, Banbury mixer, Brabender plastograph, akneader, or the like.

Examples of the plasticizer are phthalic acid esters such as dioctylphthalate (DOP), diisodecyl phthalate (DIDP), ditridecyl phthalate andbutylbenzyl phthalate (BBP), phosphoric acid esters such as tricresylphosphate (TCP) and trioctyl phosphate (TOP), fatty acid esters such astributyl citrate and methylacetyl ricinolate (MAR), polyether esterssuch as triethyleneglycol-di-2-ethylbutylate (3GH) andtetraethyleneglycoldihexanol, and mixtures of these compounds.

Examples of solvents for dissolving therein a PVB are ethyl alcohol,n-propyl alcohol, isopropyl alcohol, n-butyl alcohol and methylenechloride. Examples of solvents for dissolving therein an EVA aretoluene, xylene and methylene chloride.

After the step (f), the raw material is shaped into the interlayer filmusing a common extruder, a calender or the like. The thickness of theinterlayer film is preferably from about 0.2 to about 1.2 mm and morepreferably from about 0.3 to about 0.9 mm.

There is provided an alternative method of preparing the interlayer filmaccording to the present invention. This alternative method comprisesthe steps of:

(c) uniformly dispersing the functional ultra-fine particles having aparticle diameter within a range from 0.001 to 0.2 μm, in a solventwhich is capable of dissolving therein a PVB or an EVA, so that a firstmixture is prepared;

(d) adding the PVB or the EVA, an optional plasticizer and at least oneother optional additive to the first mixture, so that a second mixturein which the PVB or the EVA is dissolved is prepared;

(e) kneading the second mixture;

(f) shaping the kneaded second mixture into a wet film; and

(g) drying the wet film at a temperature from 50 to 110° C. into theinterlayer film.

There is provided a further alternative method of preparing theinterlayer film in accordance with the present invention. This furtheralternative method comprises the steps of:

(c) heating a PVB or an EVA at a temperature which is higher than aglass transition temperature thereof, the glass transition temperaturebeing within a range from 55 to 90° C., so that the PVB or the EVA issoftened; and

(d) adding functional ultra-fine particles having a particle diameterfrom 0.001 to 0.2 μm to the softened PVB or EVA, so that a first mixtureis prepared; and

(e) kneading the first mixture so as to uniformly disperse therein thefunctional ultra-fine particles, thereby preparing the raw material ofthe interlayer film.

The following examples are illustrative of the present invention, butthese examples are not limitative.

EXAMPLE 1

In this example, an interlayer film was prepared as follows. At first,10 g of a dioctyl phthalate solution containing 20 wt % of ATO(conductive antimony-containing tin oxide) ultra-fine particles whichhave a particle diameter up to 0.02 μm and are dispersed therein, and130 g of pure dioctyl phthalate were added to 485 g of a polyvinylbutyral resin. Then, this mixture was kneaded at about 70° C. for about15 min, with the addition of an ultraviolet ray absorbing agent and thelike, by a mixer equipped with three rollers. The thus obtained rawmaterial of the interlayer film was shaped at about 190° C. by anextruder into a film having a thickness of about 0.8 mm. With this,uniformly uneven embossing was formed on the surface of the interlayerfilm.

The thus prepared interlayer film was cut to have the same size as thatof two clear glass substrates (FL2.3) having widths of about 300 mm anda thickness of about 2.3 mm. Then, the interlayer film was interposedbetween these glass substrates to prepare a laminate. Then, thislaminate was put into a vacuum bag made of rubber. Then, the atmosphereof this bag was removed to reduce pressure thereof, and under thiscondition this bag was allowed to stand still for about 20-30 minutes ata temperature from about 80 to 110° C. Then, the temperature was loweredto room temperature. Then, the laminate was taken out of the bag andthen put into an autoclave. Then, the laminate was heated at atemperature from about 110 to about 140° C. under a pressure from about10 to about 14 kg/cm² for a period of time from about 20 to about 40minutes for bonding together the glass substrates and the interlayerfilm.

The thus obtained laminated glass was subjected to several evaluationtests, as follows. In optical characteristics tests, the transmittanceof the laminated glass for the light having a wavelength from 340 to1,800 nm was measured with 340 type automated spectrophotometer (tradename) made by Hitachi Ltd. With this, the visible light transmittance Tv(380-780 nm), the solar radiation transmittance Ts (340-1,800 nm),excitation purity (Pe) and the color tone of the laminated glass weredetermined in accordance with Japanese Industrial Standard (JIS) Z 8722and JIS R 3106 OR JIS Z 8701. In these tests, Tv was about 76.8%, Ts wasabout 58.6%, Pe was about 0.7%, and the color tone was a neutral palegray. The laminated glass did not have glare caused by reflection.

The haze value (H) was determined in accordance with JIS K6714. Hazevalues of up to 3% and up to 1% were judged as being satisfactory asarchitectural and automotive laminated glasses, respectively. The resultof this haze value test was about 0.3%.

In radio wave transmittance test, the value of reflection loss (dB) ofthe laminated glass within a radio wave frequency from 10 to 1,000 MHzwas compared with that of a clear glass plate (FL3t) in accordance withthe KEC method using an electric field shield effect meter. Thelaminated glass was judged as being satisfactory in this test, becausethe result of the laminated glass according to this example wasequivalent to that of the clear glass plate, and because the absolutevalue of the difference therebetween was not greater than 2 dB.

In bond strength test, the laminated glass was allowed to stand still ata temperature from −18.6 to −17.4° C. for a period of time from 12 to 20hr. Then, the laminated glass was hit by a hammer to break the glassplate thereof. The laminated glass was judged as being satisfactory,because the degree of exposure of the interlayer film was notsignificant.

In a heat resistance test, the laminated glass was put into boilingwater at 100° C. for about 2 hr. The laminated glass was judged as beingsatisfactory, because the laminated glass, except its peripheral portionhaving a width of 10 mm, after this test did not have abnormalities suchas the occurrence of bubbles, clouds, cracks and the like.

In a humidity resistance test, the laminated glass was allowed to standstill in an atmosphere of a temperature from 48 to 52° C. and a humidityfrom 91 to 99% for two weeks. The laminated glass was judged as beingsatisfactory, because the laminated glass after this test did not haveabnormalities such as the occurrence of bubbles, clouds, crack and thelike.

In an electrical characteristic test, the sheet resistivity of thelaminated glass was measured with a surface resistivity meter (HIRESTAHT-210 (trade name) made by Mitsubishi Petrochemical Co., Ltd.). In thistest, the laminated glass was judged as being satisfactory because ithad a sheet resistivity of at least 10 MΩ/□.

In addition to the above-mentioned tests, a weatherability test and someother tests were conducted. The laminated glass was judged as beingsatisfactory in these tests, too. For example, the visible lighttransmittance was determined before and after the weatherability testfor about 1,000 hr with a sunshine weathermeter. The laminated glass hadsubstantially the same transmittance before and after this test.Therefore, it was judged as being satisfactory in this test.

EXAMPLE 2

In this example, an interlayer film was prepared as follows. At first,10 g of a triethyleneglycol-di-2-ethylbutyrate (3GH) solution containing20 wt % of ATO (conductive antimony-containing tin oxide) ultra-fineparticles which have a particle diameter up to 0.02 μm and are dispersedtherein, and 130 g of pure 3GH were added to 485 g of a polyvinylbutyral resin. Then, this mixture was kneaded at about 70° C. for about15 min, with the addition of 5 g of a bond adjusting agent (TOSPEARL120(trade name) made by Toshiba Silicone Co.), an ultraviolet ray absorbingagent and the like, by a mixer equipped with three rollers. The thusobtained raw material of the interlayer film was shaped at about 190° C.by an extruder into a film having a thickness of about 0.8 mm. Withthis, uniformly uneven embossing was formed on the surface of theinterlayer film.

The thus prepared interlayer film was cut to have the same size as thatof two clear glass substrates (FL2) having widths of about 300 mm and athickness of about 2.0 mm. Then, the interlayer film was interposedbetween these glass substrates to prepare a laminate. Then, a laminatedglass was prepared from this laminate in the same manner as in Example1.

The same evaluation tests as those of Example 1 were conducted on thelaminated glass. The laminated glass was satisfactory with respect toeach evaluation test. For example, Tv was 76.5%, Ts was 58.5%, and H was0.4%.

EXAMPLE 3

In this example, an interlayer film was prepared as follows. At first,10 g of a butylbenzyl phthalate (BBP) solution containing 20 wt % of ITO(conductive tin-containing indium oxide) ultra-fine particles which havea particle diameter up to 0.1 μm and are dispersed therein, and 90 g ofpure BBP were added to 323 g of a polyvinyl butyral resin. Then, fromthis mixture, an interlayer film having a thickness of about 0.8 mm wasprepared in the same manner as in Example 1. With this, uniformly unevenembossing was formed on the surface of the interlayer film.

Using the thus prepared interlayer film and the same two glasssubstrates as those of Example 2, a laminated glass was prepared in thesame manner as in Example 1.

The same evaluation tests as those of Example 1 were conducted on thelaminated glass. The laminated glass was satisfactory with respect toeach evaluation test. For example, Tv was 76.3%, Ts was 51.5%, and H was0.4%. Furthermore, the pummel value was about 7-8. Therefore, thelaminated glass was judged as being suitable as an architecturallaminated glass.

EXAMPLE 4

In this example, Example 3 was repeated except in that 5 g of a bondadjusting agent (TOSPAL120 (trade name) made by Toshiba Silicone Co.)was additionally added in the preparation of the raw material of theinterlayer film. Then, an interlayer film having a thickness of about0.8 mm was prepared in the same manner as in Example 1. With this,uniformly uneven embossing was formed on the surface of the interlayerfilm.

Using the thus prepared interlayer film and the same two glasssubstrates as those of Example 2, a laminated glass was prepared in thesame manner as in Example 1.

The same evaluation tests as those of Example 1 were conducted on thelaminated glass. The laminated glass was satisfactory with respect toeach evaluation test. For example, Tv was 76.2%, Ts was 51.6%, and H was0.4%. Furthermore, the pummel value was about 3-4. Therefore, thelaminated glass was judged as being suitable as an automotive laminatedglass.

EXAMPLE 5

In this example, Example 3 was repeated except in that 10 g of anorganic heat-absorbing agent was additionally added in the preparationof the raw material of the interlayer film. Then, an interlayer filmhaving a thickness of about 0.8 mm was prepared in the same manner as inExample 1. With this, uniformly uneven embossing was formed on thesurface of the interlayer film.

Using the thus prepared interlayer film and the same two glasssubstrates as those of Example 2, a laminated glass was prepared in thesame manner as in Example 1.

The same evaluation tests as those of Example 1 were conducted on thelaminated glass. The laminated glass was satisfactory with respect toeach evaluation test. For example, Tv was 64.3%, Ts was 32.8%, and H was0.4%.

EXAMPLE 6

In this example, an interlayer film was prepared as follows. At first, 7g of a diisodecyl phthalate (DIDP) solution containing 20 wt % of ITO(conductive tin-containing indium oxide) ultra-fine particles which havea particle diameter up to 0.1 μm and are dispersed therein, and 95 g ofpure DIDP were added to 323 g of a polyvinyl butyral resin. Then, fromthis mixture, an interlayer film having a thickness of about 0.8 mm wasprepared in the same manner as in Example 1. With this, uniformly unevenembossing was formed on the surface of the interlayer film.

Using the thus prepared interlayer film, one glass substrate which isthe same as one of those of Example 1, and another green glass substrate(NFL2), a laminated glass was prepared in the same manner as in Example1.

The same evaluation tests as those of Example 1 were conducted on thelaminated glass. The laminated glass was satisfactory with respect toeach evaluation test. For example, Tv was 73.3%, Ts was 42.0%, and H was0.2%.

EXAMPLE 7

In this example, Example 6 was repeated except in that 5 g of a bondadjusting agent (TOSPEARL120 (trade name) made by Toshiba Silicone Co.)was additionally added in the preparation of the raw material of theinterlayer film. Then, an interlayer film having a thickness of about0.8 mm was prepared in the same manner as in Example 1. With this,uniformly uneven embossing was formed on the surface of the interlayerfilm.

Using the thus prepared interlayer film and the same two glasssubstrates as those of Example 6, a laminated glass was prepared in thesame manner as in Example 1.

The same evaluation tests as those of Example 1 were conducted on thelaminated glass. The laminated glass was satisfactory with respect toeach evaluation test. For example, Tv was 73.2%, Ts was 42.1%, and H was0.2%.

EXAMPLE 8

In this example, Example 6 was repeated except in that the green glasssubstrate was replaced by a blue glass substrate (BFL2) in thepreparation of the laminated glass.

The same evaluation tests as those of Example 1 were conducted on thelaminated glass. The laminated glass was satisfactory with respect toeach evaluation test. For example, Tv was 76.0%, Ts was 49.5%, and H was0.2%.

EXAMPLE 9

In this example, Example 6 was repeated except in that the green glasssubstrate was replaced by a bronze glass substrate (MFL2) in thepreparation of the laminated glass.

The same evaluation tests as those of Example 1 were conducted on thelaminated glass. The laminated glass was satisfactory with respect toeach evaluation test. For example, Tv was 75.1%, Ts was 52.1%, and H was0.2%.

EXAMPLE 10

In this example, Example 6 was repeated except in that the green glasssubstrate was replaced by a gray glass substrate (GFL2) in thepreparation of the laminated glass.

The same evaluation tests as those of Example 1 were conducted on thelaminated glass. The laminated glass was satisfactory with respect toeach evaluation test. For example, Tv was 76.0%, Ts was 54.5%, and H was0.2%.

EXAMPLE 11

In this example, an interlayer film was prepared as follows. At first,20 g of a DOP solution and 120 g of pure tricresyl phosphate (TCP) wereadded to 480 g of a polyvinyl butyral resin to prepare a mixture. ThisDOP solution contained 40 wt % of TM3410 (trade name) made by DainichiSeika Kogyo Co., that is, ultra-fine particles of an inorganic pigmentmixture of Co₂O₃ and Al₂O₃, which have a particle diameter from 0.01 to0.02 μm and are dispersed in the solution. Then, an interlayer filmhaving a thickness of about 0.8 mm was prepared from the above mixturein the same manner as in Example 1. Using the thus prepared interlayerfilm, a laminated glass was prepared in the same manner as in Example 1.

The same evaluation tests as those of Example 1 were conducted on thelaminated glass. The laminated glass was satisfactory with respect toeach evaluation test. For example, Tv was 73.8%, Ts was 50.2%, Pe was7.8%, and H was 0.2%. The laminated glass had a clear blue color tone.

EXAMPLE 12

In this example, an interlayer film was prepared as follows. At first,30 g of a DOP solution and 100 g of pure methylacetyl ricinolate (MAR)were added to 480 g of a polyvinyl butyral resin to prepare a mixture.This DOP solution contained 30 wt % of TM3320 (trade name) made byDainichi Seika Kogyo Co., that is, ultra-fine particles of an inorganicpigment mixture of TiO₂, NiO, Co₂O₃ and ZnO which have a particlediameter from 0.01 to 0.02 μm and are dispersed in the solution. Then,an interlayer film having a thickness of about 0.8 mm was prepared fromthe above mixture in the same manner as in Example 1. Using the thusprepared interlayer film, a laminated glass was prepared in the samemanner as in Example 1.

The same evaluation tests as those of Example 1 were conducted on thelaminated glass. The laminated glass was satisfactory with respect toeach evaluation test. For example, Tv was 77.8%, Ts was 60.2%, and H was0.2%. Pe was 13.8%, and thus the laminated glass had a clear green colortone.

EXAMPLE 13

In this example, an interlayer film was prepared as follows. At first,20 g of a DOP solution and 150 g of pure 3GH were added to 480 g of apolyvinyl butyral resin to prepare a mixture. This DOP solutioncontained 30 wt % of TM3210 (trade name) made by Dainichi Seika KogyoCo., that is, ultra-fine particles of an inorganic pigment mixture ofFe₂O₃, ZnO and Cr₂O₃ which have a particle diameter from 0.01 to 0.02 μmand are dispersed in the solution. Then, an interlayer film having athickness of about 0.8 mm was prepared from the above mixture in thesame manner as in Example 1. Using the thus prepared interlayer film, alaminated glass was prepared in the same manner as in Example 1.

The same evaluation tests as those of Example 1 were conducted on thelaminated glass. The laminated glass was satisfactory with respect toeach evaluation test. For example, Tv was 67.8%, Ts was 51.8%, and H was0.2%. Pe was a slightly high value, but the laminated glass had a cleargreen color tone.

EXAMPLE 14

In this example, an interlayer film was prepared as follows. At first,10 g of a methylethyl ketone solution containing 20 wt % of the ATOultra-fine particles dispersed in the solution, and 150 g of pure 3GHwere added to 490 g of a polyvinyl butyral resin. Then, this mixture waskneaded, with the addition of the bond adjusting agent, the ultravioletray absorbing agent and the like, by a mixer equipped with threerollers, at about 80° C. under a pressure of about 20 mm Hg for about 1hr. Then, from this kneaded mixture, an interlayer film having athickness of about 0.8 mm was prepared in the same manner as inExample 1. Using the thus prepared interlayer film, a laminated glasswas prepared in the same manner as in Example 1.

The same evaluation tests as those of Example 1 were conducted on thelaminated glass. The laminated glass was satisfactory with respect toeach evaluation test. For example, Tv was 76.4%, Ts was 51.6%, and H was0.4%.

EXAMPLE 15

In this example, an interlayer film was prepared as follows. At first,490 g of a polyvinyl butyral resin was heated at about 100° C. such thatthis resin became a syrupy condition. Under this condition, 2 g of theATO ultra-fine particles were added to this resin. Then, this mixturewas kneaded, with the addition of the ultraviolet ray absorbing agentand the like, by a mixer equipped with three rollers, at about 80° C.for about 1 hr. Then, from this kneaded mixture, an interlayer filmhaving a thickness of about 0.8 mm was prepared in the same manner as inExample 1. Using the thus prepared interlayer film, a laminated glasswas prepared in the same manner as in Example 1.

The same evaluation tests as those of Example 1 were conducted on thelaminated glass. The laminated glass was satisfactory with respect toeach evaluation test. For example, Tv was 77.5%, Ts was 55.7%, and H was0.2%.

It is needless to say that pummel values of the laminated glasses ofExamples 1, 2 and 5-15 can be adjusted for use as an architectural orautomotive laminated glass.

What is claimed is:
 1. A method of producing a laminated glass,comprising the steps of: (a) interposing an interlayer film betweenfirst and second glass plates, said interlayer film comprising apolyvinyl butyral or an ethylene-vinylacetate copolymer, said interlayerfilm comprising functional ultra-fine particles which are dispersedtherein and have a particle diameter of up to 0.2 μm, thereby providinginsulation against heat caused by solar radiation, said functionalultra-fine particles comprising at least one member selected from thegroup consisting of an antimony-doped tin oxide, a tin-doped indiumoxide, a mixture of Co₂O₃ and Al₂O₃, a mixture of TiO₂, NiO, Co₂O₃ andZnO, and a mixture of Fe₂O₃, ZnO and Cr₂O₃; and (b) bonding togethersaid first and second glass plates and said interlayer film.
 2. A methodaccording to claim 1, wherein said interlayer film is made of a rawmaterial prepared by a method comprising the steps of: (c) dispersing upto 80.0 wt % of said functional ultra-fine particles in a plasticizersolution, based on the total weight of said plasticizer solution andsaid ultra-fine particles, so as to prepare a first mixture; (d) addingup to 50 wt % of said first mixture to a polyvinyl butyral or anethylene-vinylacetate copolymer, based on the total weight of saidpolyvinyl butyral or said ethylene-vinylacetate copolymer, so as toprepare a second mixture; (e) optionally adding at least one additive tosaid second mixture so as to prepare a third mixture; and (f) kneadingsaid third mixture to uniformly disperse therein said functionalultra-fine particles, thereby to prepare said raw material.
 3. A methodaccording to claim 2, wherein, during the step (c), up to 20.0 wt % ofsaid functional ultra-fine particles are dispersed in said plasticizersolution.
 4. A method according to claim 1, wherein said interlayer filmis prepared by a method comprising the steps of: (c) uniformlydispersing said functional ultra-fine particles having a particlediameter within a range from 0.001 to 0.2 μm, in a solvent which iscapable of dissolving therein a polyvinyl butyral or anethylene-vinylacetate copolymer, so that a first mixture is prepared;(d) adding said polyvinyl butyral or said ethylene-vinylacetatecopolymer, an optional plasticizer and at least one other optionaladditive to said first mixture, so that a second mixture in which saidpolyvinyl butyral or said ethylene-vinylacetate copolymer is dissolvedis prepared; (e) kneading said second mixture; (f) shaping said kneadedsecond mixture into a film; and (g) drying said film at a temperaturefrom 50 to 110° C. into said interlayer film.
 5. A method according toclaim 1, wherein said interlayer film is made of a raw material which isprepared by a method comprising the steps of: (c) heating a polyvinylbutyral or an ethylenevinyl-acetate copolymer at a temperature which ishigher than a glass transition temperature thereof, said glasstransition temperature being within a range from 55 to 90° C., so thatsaid polyvinyl butyral or said ethylene-vinylacetate copolymer issoftened; and (d) adding functional ultra-fine particles having aparticle diameter from 0.001 to 0.2 μm to said softened polyvinylbutyral or said softened ethylene-vinylacetate copolymer, so that afirst mixture is prepared; and (e) kneading said first mixture so as touniformly disperse therein said functional ultra-fine particles, therebypreparing said raw material.
 6. A method according to claim 1, whereinsaid functional ultra-fine particles comprise a mixture of said at leastone member and an organic resin to reduce bond strength between saidinterlayer film and said first and second glass plates.
 7. A methodaccording to claim 6, wherein said ultra-fine particles comprise said atleast one member coated with said organic resin.
 8. A method accordingto claim 1, wherein the step (b) is conducted in an autoclave, or for aperiod of time from 20 to 40 minutes under a pressure of from about 10to about 14 kg/cm₂, while an ambient temperature is raised from 110 to140° C.
 9. A method according to claim 1, wherein said functionultra-fine particles comprise a conductive tin-containing indium oxide.10. A method according to claim 1, wherein said functional ultra-fineparticles comprise In₂O₃ doped with Sn.
 11. A method according to claim1, wherein said functional ultra-fine particles comprise an indium tinoxide.
 12. A method according to claim 1, wherein said laminated glassis radio wave transmittable.
 13. A method according to claim 1, whereinan embossing is formed on a surface of said interlayer film.
 14. Amethod according to claim 1, wherein a surface of said first and secondglass plates is coated with a primer or an organic resin to reduce bondstrength between said interlayer film and said first and second glassplates.
 15. A method according to claim 1, wherein said functionalultra-fine particles comprise antimony-doped tin oxide.
 16. A methodaccording to claim 15, wherein said functional ultra-fine particlescomprise SnO₂ doped with Sb.
 17. A method according to claim 15, whereinsaid functional ultra-fine particles comprise SnO₂ doped with Sb₂O₃. 18.A method according to claim 15, wherein said functional ultra-fineparticles comprise a conductive antimony-containing tin oxide. 19.method according to claim 1, wherein said functional ultra-fineparticles comprise tin-doped indium oxide.
 20. A method according toclaim 19, wherein said functional ultra-fine particles comprise amixture of In₂O₃ and SnO₂.